Sex difference in neurological outcome and post-cardiac arrest care in out-of-hospital cardiac arrest patients treated with targeted temperature management

Type of funding sources: None.

Conflicting results regarding sex-based differences in the outcomes of out-of-hospital cardiac arrest (OHCA) patients have been reported. Furthermore, no study has examined whether differences in in-hospital interventions and courses are driven by sex differences. This study evaluated the effect of sex on the in-hospital course of these patients as well as the survival rates and long-term neurological outcomes of comatose OHCA patients treated with targeted temperature management (TTM).

We retrospectively analyzed the Korean Hypothermia Network prospective registry composed of data collected from 22 hospitals in Korea between October 2015 and December 2018. To evaluate the effect of sex on patient outcomes, we created various multivariate logistic regression models including baseline characteristics, resuscitation, and in-hospital care variables with an interaction term (age × sex). We also performed a stratified analysis of different age groups (less than 50 years of age and older). Regarding the difference in in-hospital courses, we compared daily total and SOFA sub-scores between the sexes and analyzed whether the decision regarding early cardiac interventions and limitations in in-hospital care were associated with sex.

Among 1339 patients included in the study, 952 were men and 387 were women. There were no differences in age or modified comorbidity index values between the gender groups. Women were more likely to experience cardiac arrest at home and unwitnessed arrests, whereas men were more likely to have shockable initial rhythm, cardiac cause arrest, and ST-segment elevation myocardial infarction (STEMI) on initial electrocardiography and undergo early coronary interventions. The rate of survival to discharge was similar, but men showed better 6-month neurological outcomes. After adjusting for confounders, the male sex was not associated with survival to discharge or good 6-month neurological outcomes. There was no association between sex and outcome in patients of reproductive age and no interaction between age and sex. Regarding the in-hospital course, the daily total and SOFA sub-scores were similar in both sexes. The adjusted effect of sex was not associated with the clinician’s decision to perform early cardiac interventions. The decision to discontinue life-sustaining treatment was determined by poor prognostic factors, not by sex.

The findings suggested that men had more favorable 6-month survivals and good neurological outcomes compared to women since they had more favorable resuscitation variables. However, after adjusting for confounders, there was no difference between the sexes. This result was consistent with the data in patients of reproductive age. The results regarding in-hospital course showed that daily patient severity scores, early cardiac interventions, resource consumption, and the rates of withdrawal/withholding of in-hospital care were similar in men and women.